CacheBeanDefinitionParser.java

/*
 * Copyright 2013-2014 the original author or authors.
 *
 * Licensed under the Apache License, Version 2.0 (the "License");
 * you may not use this file except in compliance with the License.
 * You may obtain a copy of the License at
 *
 *      http://www.apache.org/licenses/LICENSE-2.0
 *
 * Unless required by applicable law or agreed to in writing, software
 * distributed under the License is distributed on an "AS IS" BASIS,
 * WITHOUT WARRANTIES OR CONDITIONS OF ANY KIND, either express or implied.
 * See the License for the specific language governing permissions and
 * limitations under the License.
 */

package org.springframework.cloud.aws.cache.config.xml;

import org.springframework.beans.factory.BeanDefinitionStoreException;
import org.springframework.beans.factory.config.BeanDefinition;
import org.springframework.beans.factory.config.RuntimeBeanReference;
import org.springframework.beans.factory.support.AbstractBeanDefinition;
import org.springframework.beans.factory.support.BeanDefinitionBuilder;
import org.springframework.beans.factory.support.ManagedList;
import org.springframework.beans.factory.xml.AbstractSingleBeanDefinitionParser;
import org.springframework.beans.factory.xml.ParserContext;
import org.springframework.cloud.aws.context.config.xml.GlobalBeanDefinitionUtils;
import org.springframework.util.ClassUtils;
import org.springframework.util.StringUtils;
import org.springframework.util.xml.DomUtils;
import org.w3c.dom.Element;

import java.util.List;

import static org.springframework.cloud.aws.core.config.xml.XmlWebserviceConfigurationUtils.getCustomClientOrDefaultClientBeanName;

/**
 * Parser for the {@code <aws-cache:cache-manager />} element.
 *
 * @author Alain Sahli
 * @author Agim Emruli
 * @since 1.0
 */
class CacheBeanDefinitionParser extends AbstractSingleBeanDefinitionParser {

    private static final String CACHE_MANAGER = "cacheManager";
    private static final String CACHE_CLUSTER_ELEMENT_NAME = "cache-cluster";
    private static final String CACHE_REF_ELEMENT_NAME = "cache-ref";

    private static final String ELASTICACHE_FACTORY_BEAN = "org.springframework.cloud.aws.cache.ElastiCacheFactoryBean";
    private static final String ELASTI_CACHE_CLIENT_CLASS_NAME = "com.amazonaws.services.elasticache.AmazonElastiCacheClient";
    private static final String MEMCACHED_FACTORY_CLASS_NAME = "org.springframework.cloud.aws.cache.memcached.MemcachedCacheFactory";
    private static final String REDIS_CONNECTION_FACTORY_CLASS_NAME = "org.springframework.cloud.aws.cache.redis.RedisCacheFactory";

    @Override
    protected String getBeanClassName(Element element) {
        return "org.springframework.cache.support.SimpleCacheManager";
    }

    @Override
    protected void doParse(Element element, ParserContext parserContext, BeanDefinitionBuilder builder) {
        if (parserContext.getRegistry().containsBeanDefinition(CACHE_MANAGER)) {
            parserContext.getReaderContext().error("Only one cache manager can be defined", element);
        }

        builder.addPropertyValue("caches", createCacheCollection(element, parserContext));
    }

    @Override
    protected String resolveId(Element element, AbstractBeanDefinition definition, ParserContext parserContext) throws BeanDefinitionStoreException {
        return CACHE_MANAGER;
    }

    private ManagedList<Object> createCacheCollection(Element element, ParserContext parserContext) {
        ManagedList<Object> caches = new ManagedList<>();
        List<Element> cacheElements = DomUtils.getChildElements(element);

        for (Element cacheElement : cacheElements) {
            String elementName = cacheElement.getLocalName();

            switch (elementName) {
                case CACHE_REF_ELEMENT_NAME:
                    caches.add(new RuntimeBeanReference(cacheElement.getAttribute("ref")));
                    break;
                case CACHE_CLUSTER_ELEMENT_NAME:
                    String cacheClusterId = getRequiredAttribute("name", cacheElement, parserContext);
                    caches.add(createElastiCacheFactoryBean(cacheElement, parserContext, cacheClusterId, createDefaultCacheFactories(cacheElement, parserContext)));
                    break;
                default:
                    parserContext.getReaderContext().error("Unknown element detected", parserContext.extractSource(cacheElement));
            }
        }
        return caches;
    }

    private static String getRequiredAttribute(String attributeName, Element source, ParserContext parserContext) {
        if (StringUtils.hasText(source.getAttribute(attributeName))) {
            return source.getAttribute(attributeName);
        } else {
            parserContext.getReaderContext().error("Attribute '" + attributeName + "' is required", source);
            return null;
        }
    }

    private static ManagedList<BeanDefinition> createDefaultCacheFactories(Element element, ParserContext parserContext) {
        ManagedList<BeanDefinition> result = new ManagedList<>();
        result.setSource(parserContext.extractSource(element));
        if (ClassUtils.isPresent("net.spy.memcached.MemcachedClient", parserContext.getReaderContext().getBeanClassLoader())) {
            result.add(getCacheFactory(MEMCACHED_FACTORY_CLASS_NAME, element));
        }

        if (ClassUtils.isPresent("org.springframework.data.redis.connection.RedisConnectionFactory", parserContext.getReaderContext().getBeanClassLoader())) {
            result.add(getCacheFactory(REDIS_CONNECTION_FACTORY_CLASS_NAME, element));
        }
        return result;
    }

    private static BeanDefinition createElastiCacheFactoryBean(Element source, ParserContext parserContext, String clusterId, ManagedList<BeanDefinition> cacheFactories) {
        BeanDefinitionBuilder beanDefinitionBuilder = BeanDefinitionBuilder.rootBeanDefinition(ELASTICACHE_FACTORY_BEAN);
        beanDefinitionBuilder.addConstructorArgReference(getCustomClientOrDefaultClientBeanName(source, parserContext,
                "amazon-elasti-cache", ELASTI_CACHE_CLIENT_CLASS_NAME));
        beanDefinitionBuilder.addConstructorArgValue(clusterId);
        beanDefinitionBuilder.addConstructorArgReference(GlobalBeanDefinitionUtils.retrieveResourceIdResolverBeanName(parserContext.getRegistry()));
        beanDefinitionBuilder.addConstructorArgValue(cacheFactories);
        return beanDefinitionBuilder.getBeanDefinition();
    }

    private static BeanDefinition getCacheFactory(String className, Element element) {
        BeanDefinitionBuilder builder = BeanDefinitionBuilder.genericBeanDefinition(className);
        if (StringUtils.hasText(element.getAttribute("expiration"))) {
            builder.addPropertyValue("expiryTime", element.getAttribute("expiration"));
        }
        return builder.getBeanDefinition();
    }
}